| 318 | | Ivan: Inclusion and choice of GPS antenna, for timing to base station [[BR]] |
| 319 | | Candidate is [http://www.antenna.com/apg_products.cgi?id_num=11092 PCTel GPS-TMG-SP-40NGPS] timing reference antenna, with integrated lightning protection [[BR]] |
| 320 | | ISSUE: Pick antenna with appropriate gain, and coax cable with appropriate attenuation. [[BR]] |
| 321 | | |
| 322 | | |
| 323 | | |
| 324 | | The same antenna/mounting combo comes with 10, 20 and 40 dB of gain (the only issue is possible ringing with high gains so for cases where there is less than 50m of cable we should go with 10 or 20 dB max). I would definitely go for heavy duty mounting (like this one because it has built-in arrester so that all we need is a proper grounding which presumably already exist for the main antenna). As for what cable and where to get them, there are quite a few outfits; for example the site for WiMAX antenna: |
| 325 | | |
| 326 | | http://www.l-com.com/category.aspx?id=15 |
| 327 | | |
| 328 | | Ivan. |
| 329 | | |
| 330 | | -----Original Message----- |
| 331 | | From: Harry Mussman [mailto:hmussman@bbn.com] |
| 332 | | Sent: Wednesday, March 31, 2010 11:37 AM |
| 333 | | To: 'michel,tony'; Ivan Seskar |
| 334 | | Cc: 'Harry Mussman' |
| 335 | | Subject: gps antenna and cable |
| 336 | | |
| 337 | | Tony and Ivan, |
| 338 | | |
| 339 | | I am updating the wiki, and am looking for: |
| 340 | | |
| 341 | | |
| 342 | | 1) gps antenna spec. |
| 343 | | |
| 344 | | Per Ivan earlier, a good one is attached. |
| 345 | | |
| 346 | | Which mounting hardware? Heavy duty? |
| 347 | | |
| 348 | | |
| 349 | | |
| 350 | | 2) gps antenna coax cable |
| 351 | | |
| 352 | | Assume: up to 100m, like fiber? |
| 353 | | |
| 354 | | Overall loss budget: |
| 355 | | |
| 356 | | Output from antenna? |
| 357 | | |
| 358 | | Input range to NEC ODU? |
| 359 | | |
| 360 | | What coax, loss? |
| | 318 | A GPS antenna assembly is provided, and connected to the IDU, to provide a stable and precise timing source to the base station. The antenna assembly is connected to the IDU using a 50-ohm coax, that carries the receivedsignal to the IDU, and power to the antenna assembly. [[BR]] |
| | 319 | |
| | 320 | The GPS antenna assembly can be mounted in any outdoor location where it can "see" the sky, but we will assume that it is mounted in the same location as the WiMAX antenna. |
| | 321 | |
| | 322 | |
| | 323 | The suggested GPS antenna assembly is the [http://www.antenna.com/apg_products.cgi?id_num=11092 PCTel GPS-TMG-SPS-40NCB] timing reference antenna. It provides: |
| | 324 | * integrated lightning protection [[BR]] |
| | 325 | * heavy duty mounting clamp |
| | 326 | * amplifier with 40 dB of gain |
| | 327 | |
| | 328 | The amplifier with 40 dB of gain compensates for loss in the 50-ohm coax cable run from the GPS antenna assembly at outside site, to the IDU at the indoor site. |
| | 329 | |
| | 330 | The suggested 50-ohm coax cable is [http://www.l-com.com/multimedia/diagrams/D_RG58C-_.JPG RG58C/U], which has a loss at the GPS frequency of approxiamately 1000MHz of 40 dB for 200 ft of cable. |
| | 331 | |
| | 332 | Typical cable components:[[BR]] |
| | 333 | * [http://www.l-com.com/productfamily.aspx?id=70 BNC-male to BNC-male cable], multiple lengths.[[BR]] |
| | 334 | * [http://www.l-com.com/item.aspx?id=347 BNC-male to BNC-male cable], 200 ft length.[[BR]] |
| | 335 | * [http://www.l-com.com/item.aspx?id=5261 BNC-female to BNC-female connector], to join two cables with N-male connectors. [[BR]] |
| | 336 | * [http://www.l-com.com/item.aspx?id=5261 BNC-female to N-male connector], to join a BNC-male cable to the GPS antenna assembly [[BR]] |
| | 337 | |
| | 338 | |
